US4695445A - Magnesium hydroxide and process for its production - Google Patents

Magnesium hydroxide and process for its production Download PDF

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Publication number
US4695445A
US4695445A US06/895,464 US89546486A US4695445A US 4695445 A US4695445 A US 4695445A US 89546486 A US89546486 A US 89546486A US 4695445 A US4695445 A US 4695445A
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Prior art keywords
magnesium hydroxide
magnesium
concentration
accordance
aqueous solution
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US06/895,464
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English (en)
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Keiichi Nakaya
Kunio Tanaka
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AGC Inc
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Asahi Glass Co Ltd
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Assigned to ASAHI GLASS COMPANY LTD., NO. 1-2, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO, JAPAN reassignment ASAHI GLASS COMPANY LTD., NO. 1-2, MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO, JAPAN ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: NAKAYA, KEIICHI, TANAKA, KUNIO
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    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K3/00—Use of inorganic substances as compounding ingredients
    • C08K3/18—Oxygen-containing compounds, e.g. metal carbonyls
    • C08K3/20—Oxides; Hydroxides
    • C08K3/22—Oxides; Hydroxides of metals
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
    • C01F5/00—Compounds of magnesium
    • C01F5/14—Magnesium hydroxide
    • C01F5/20—Magnesium hydroxide by precipitation from solutions of magnesium salts with ammonia
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/20—Particle morphology extending in two dimensions, e.g. plate-like
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/54—Particles characterised by their aspect ratio, i.e. the ratio of sizes in the longest to the shortest dimension
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/62—Submicrometer sized, i.e. from 0.1-1 micrometer

Definitions

  • the present invention relates to magnesium hydroxide of a fine plate-like crystal form, and a process for its production. More particularly, it relates to fine particulate magnesium hydroxide having excellent dispersibility and anti-agglomeration properties and thus being useful as a fire retardant filler for a thermoplastic resin.
  • Japanese Unexamined Patent Publication No. 83952/1979 discloses a product having a BET specific surface area of not higher than 20 m 2 /g and a BET specific surface area/Brane method specific surface area ratio of from about 1 to about 3, as a fire retardant filler for a thermoplastic resin, and it discloses that for the production of such magnesium hydroxide, the process disclosed in Japanese Unexamined Patent Publication No. 115799/1977 can be employed.
  • the process disclosed in Japanese Unexamined Patent Publication No. 115799/1977 comprises heating basic magnesium chloride or nitrate in an aqueous medium under a pressurized condition.
  • the magnesium hydroxide obtained by the disclosed process is not necessarily satisfactory from the viewpoint of incorporation into a resin, and no crystal form is disclosed although the magnesium hydroxide is disclosed to have a small crystal distortion.
  • magnesium hydroxide having a fine, thin and relatively uniform particle form.
  • Another object of the present invention is to provide a convenient means for the production of magnesium hydroxide of a fine plate-like particle form having minimum agglomeration properties, without necessity to employ a cumbersome method as disclosed in Japanese Unexamined Patent Publication No. 115799/1977.
  • the present invention provides magnesium hydroxide of a fine plate-like particle form having an average particle size (d) of from 0.2 to 0.8 ⁇ m as measured by a light transmission type liquid phase sedimentation method, wherein the proportion of particles having a particle size of d+0.5 ⁇ m or larger is not higher than 50% by weight based on the weight of the total particles, and the particle thickness distribution is such that the proportion of particles having a thickness of 0.05 ⁇ m or less is not higher than 5% by number and the proportion of particles having a thickness of 0.2 ⁇ m or more is not higher than 20% by number.
  • the present invention provides a process for producing magnesium hydroxide which comprises reacting an aqueous solution containing a water soluble magnesium salt, with ammonia and precipitating formed magnesium hydroxide from the aqueous solution, wherein the precipitation of magnesium hydroxide is initiated when the concentration of magnesium hydroxide dissolved in the aqueous solution reaches a level equal to or higher than C S represented by the following formula:
  • C S is the concentration (g mol/liter) of magnesium hydroxide dissolved in the aqueous solution at the initiation of the precipitation of magnesium hydroxide
  • C M is the concentration (g mol/liter) of magnesium ions in the aqueous solution containing the water soluble magnesium salt to be reacted with ammonia, so as to obtain magnesium hydroxide having the above-mentioned characteristics.
  • FIG. 1 is an electron microscopic photograph showing the plan view of particles of magnesium hydroxide of the present invention.
  • FIG. 2 is an electron microscopic photograph showing the side view of the same particles.
  • FIG. 3 is a graph showing the thickness distribution curve of the magnesium hydroxide of the present invention shown in FIG. 1.
  • FIG. 4 is a graph showing the particle size distribution curve of the magnesium hydroxide of the present invention, as obtained by a light transmission type liquid phase sedimentation method.
  • the magnesium hydroxide of the present invention is very fine and plate-like and has a uniform particle size distribution and thickness distribution.
  • the fine plate-like structure of the magnesium hydroxide of the present invention is evident from FIGS. 1 and 2 showing the electron microscopic plan view and side view, respectively, of particles of the magnesium hydroxide of the present invention.
  • FIG. 3 shows the thickness distribution curve of the magnesium hydroxide particles of the present invention.
  • the thickness distribution curve was obtained by the following method.
  • a magnesium hydroxide sample was kneaded with a resin such as a polyethylene resin, and the mixture was molded into a sheet so that magnesium hydroxide crystals were oriented in a certain direction in the sheet. Then, the resin sheet having the magnesium hydroxide incorporated therein, was subjected to rupture under a frozen state, and the resin at the ruptured cross-section was removed by oxygen plasma treatment at a low temperature. A photograph of the remaining magnesium hydroxide crystals was taken by an electron microscope. Then, the thickness of magnesium hydroxide was measured, and a distribution curve of the thickness was prepared.
  • a resin such as a polyethylene resin
  • the magnesium hydroxide of the present invention has a thin plate-like form and the thickness distribution is highly uniform.
  • FIG. 4 shows a distribution curve of the particle size of the magnesium hydroxide of the present invention, as measured by a light transmission type liquid phase sedimentation method. From this particle size distribution curve, it is evident that the magnesium hydroxide of the present invention is very fine and has a uniform particle size distribution.
  • the light transmission type liquid phase sedimentation method used as a method for measuring the particle size distribution in the present invention is as follows.
  • a sample is suspended in a medium such as distilled water or an aqueous ethanol solution, whereupon the sedimentation of particles in the liquid phase is measured by a light transmission method, and the particle size distribution is determined.
  • a medium such as distilled water or an aqueous ethanol solution
  • the plate-like shape of the magnesium hydroxide of the present invention does not present the apparent hexagonal plate configuration specific to ordinary magnesium hydroxide crystals, and the periphery of each particle has a non-specific configuration with no straight portion.
  • the non-specific configuration of the magnesium hydroxide of the present invention is evident also from the photograph of FIG. 1.
  • the precipitation of magnesium hydroxide is delayed until the concentration of magnesium hydroxide dissolved in the solution reaches a certain level, and then substantial magnesium hydroxide crystals are precipitated all at once, whereby very fine magnesium hydroxide crystals having a uniform size will be obtained in a large amount. Further, when the subsequent reaction is continued under stirring, crystal growth proceeds with the fine magnesium hydroxide crystals serving as seed crystals without agglomeration of the fine magnesium hydroxide crystals, such being desirable from the viewpoint of the production efficiency.
  • the concentration of magnesium hydroxide dissolved in the solution of the reaction system at the initiation of the precipitation of magnesium hydroxide is important.
  • the reaction of the present invention can be conducted in two ways i.e. a case wherein ammonia is supplied to the aqueous solution containing the water soluble magnesium salt, and a case wherein the aqueous solution containing the water soluble magnesium salt is supplied to aqueous ammonia.
  • the concentration of magnesium hydroxide dissolved in the solution of the reaction system is meant for the concentration obtained by converting the concentration of magnesium or hydroxyl groups dissolved in the solvent, whichever is smaller, to the concentration of magnesium hydroxide.
  • the concentration of dissolved magnesium hydroxide is obtained by measuring the hydroxyl group concentration in the solution from the amount of ammonia supplied, and converting the hydroxyl group concentration to the magnesium hydroxide concentration.
  • the dissolved magnesium hydroxide concentration is determined by measuring the magnesium concentration in the solution from the amount of the water soluble magnesium salt supplied, and converting the magnesium concentration to the magnesium hydroxide concentration.
  • crystals formed at the initiation of the precipitation may not necessarily be solely of magnesium hydroxide and may possibly include crystals of other magnesium salts. However, crystals of such other magnesium salts will eventually be converted to magnesium hydroxide crystals.
  • the aqueous solution containing the water soluble magnesium salt is a clear solution containing no solid component. This means not only that the aqueous solution supplied to the reactor is clear, but also that no solid impurities enter into the aqueous solution, for instance, from the wall of the reactor.
  • the stirring of the aqueous solution is conducted as mild as possible.
  • an aqueous solution containing the water soluble magnesium salt is supplied to aqueous ammonia, it is preferred to minimize the amount of supply of this solution or to supply the solution at a small linear velocity uniformly over the entire reactor through a number of fine perforations.
  • the magnesium ion concentration in the aqueous solution containing the water soluble magnesium salt is also an important factor. Namely, it is preferred that the magnesium ion concentration itself is at least a certain level.
  • the magnesium ion concentration in the solution containing the water soluble magnesium salt may be less than the saturation concentration, but if the magnesium ion concentration is too low, such being undesirable from the viewpoint of the production efficiency. Therefore, the magnesium ion concentration C m in the aqueous solution containing the water soluble magnesium salt is preferably at least 0.1 g mol/liter, more preferably at least 0.5 g mol/liter.
  • the reaction temperature is preferably from 20° to 80° C.
  • the condition for the continuous reaction after the initiation of the precipitation of magnesium hydroxide is also important. Namely, even if a large amount of fine magnesium hydroxide crystals is formed by controlling as mentioned above, if the subsequent reaction is continued in a stand-still condition, the fine magnesium hydroxide crystals tend to agglomerate and freshly precipitated magnesium hydroxide crystals tend to accumulate thereon, eventually leading to large crystals. Therefore, the subsequent continuous reaction is preferably conducted while stirring the slurry containing the formed fine magnesium hydroxide particles.
  • This stirring may be conducted in any optional manner, for instance, by supersonic vibration, by foaming or liquid phase stirring by supplying a large amount of ammonia or the aqueous solution containing the water soluble magnesium salt, or by stirring with an impeller.
  • the stirring is preferably continued until the supply of ammonia or of the aqueous solution containing the water soluble magnesium salt is terminated.
  • the stirring of the slurry containing magnesium hydroxide precipitates is continued for at least 30 minutes after the termination of the supply of ammonia or the aqueous solution.
  • the reason is that during the stirring, aging proceeds so that it is possible to obtain magnesium hydroxide crystals with surface having small agglomeration properties (i.e. having a low surface activity).
  • the magnesium hydroxide crystals thus obtained are fine plate-like crystals having substantially uniform particle size and thickness. They have a stable surface condition with low surface activity, as mentioned above, and they have good dispersibility and non-agglomeration properties, as a filler to be incorporated into a thermoplastic resin.
  • the precipitated crystals at that time were plate-like particles having an average particle size of 0.3 ⁇ m.
  • the ammonia gas was continuously blown under stirring, and the reaction was completed by supplying ammonia in the total amount of 3.6 g mol per 1 g mol of magnesium chloride as the starting material.
  • the stirring of the slurry was continued for further 4 hours.
  • the magnesium hydroxide slurry thus obtained was observed by an optical microscope, whereby no agglomeration was observed.
  • the magnesium hydroxide was filtered, dried and observed by an electron microscope, whereby it was found to be plate-like particles having a particle size of from 0.1 to 1.5 ⁇ m as shown in FIGS. 1 and 2.
  • This magnesium hydroxide was subjected to the measurement by a light transmission type liquid phase sedimentation method, whereby the particle size distribution as shown in FIG. 4 was obtained.
  • the average particle size was 0.4 ⁇ m.
  • the proportion of particles having a particle size of 0.9 ⁇ m or larger was 20%.
  • the particle thickness distribution was such that the proportion of particles having a thickness of 0.05 ⁇ m or less was 0.5% by number, and the proportion of particles having a thickness of 0.2 ⁇ m or more was 1%.
  • the BET specific surface area was 11 m 2 /g.
  • the magnesium hydroxide was suitable as a fire retardant filler for a thermoplastic resin.
  • Magnesium hydroxide was formed in the same manner as in Example 1 except that the magnesium chloride concentration in Example 1 was varied as shown in Table 1. Table 1 further shows the dissolved magnesium hydroxide concentration at the initiation of the precipitation of magnesium hydroxide and the physical characteristics of magnesium hydroxide thereby obtained. These magnesium hydroxide particles were similar to those shown in FIGS. 1 and 2, and they were suitable for use as a fire retardant filler.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Geology (AREA)
  • Inorganic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
US06/895,464 1985-08-14 1986-08-11 Magnesium hydroxide and process for its production Expired - Fee Related US4695445A (en)

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JP60-177713 1985-08-14
JP17771385 1985-08-14

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US (1) US4695445A (enrdf_load_stackoverflow)
EP (1) EP0214494B1 (enrdf_load_stackoverflow)
JP (1) JPS62123014A (enrdf_load_stackoverflow)
CA (1) CA1254717A (enrdf_load_stackoverflow)
DE (1) DE3685782T2 (enrdf_load_stackoverflow)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT392774B (de) * 1989-05-05 1991-06-10 Veitscher Magnesitwerke Ag Feinpulveriges magnesiumhydroxid und verfahren zu dessen herstellung
US5143965A (en) * 1990-12-26 1992-09-01 The Dow Chemical Company Magnesium hydroxide having fine, plate-like crystalline structure and process therefor
US5286285A (en) * 1989-05-05 1994-02-15 Veitscher Magnesitwerke-Actien-Gesellschaft Finely powdery magnesium hydroxide and a process for preparing thereof
DE4319372A1 (de) * 1993-05-26 1994-12-01 Duslo Sp Magnesiumhydroxid und Verfahren zur dessen Herstellung
US6214313B1 (en) 1999-04-13 2001-04-10 Dravo Lime, Inc. High-purity magnesium hydroxide and process for its production
EP1344800A1 (en) * 2002-03-11 2003-09-17 MERCK PATENT GmbH Body pigment and process for preparing the same
US20070152201A1 (en) * 2006-01-05 2007-07-05 Headwaters Nanokinetix, Inc. Magnesium hydroxide nanoparticles, methods of making same and compositions incorporating same
US20070191214A1 (en) * 2006-01-31 2007-08-16 Pushpito Kumar Ghosh Process for the preparation of magnesia (MgO) from crude Mg (OH)2
US20070219081A1 (en) * 2006-03-15 2007-09-20 Council Of Scientific & Industrial Research Process for the preparation of magnesia (MgO)
WO2015089685A1 (zh) * 2013-12-16 2015-06-25 刘登富 一种阻燃剂的制备方法
CN106673027A (zh) * 2016-12-30 2017-05-17 安徽壹石通材料科技股份有限公司 一种六角片状氢氧化镁阻燃剂的制备合成方法
US10822544B2 (en) * 2013-10-29 2020-11-03 Joint Stock Company Kaustik Nanoparticles of flame retardant magnesium hydroxide and method of production the same
CN114890445A (zh) * 2022-06-08 2022-08-12 辽宁麦格尼科技有限公司 一种连续液膜合成超细氢氧化镁的方法
EP4112553A1 (de) 2021-06-29 2023-01-04 Nabaltec AG Verfahren zur herstellung von magnesiumhydroxid

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2096014A1 (en) * 1990-12-26 1992-06-27 Steven F. Mertz Magnesium hydroxide having stacked layer, crystalline structure and process therefor
AUPM985294A0 (en) * 1994-12-02 1995-01-05 Flamemag International Gie Magnesium process
AU685215B2 (en) * 1994-01-21 1998-01-15 Qmc (Flamemag) Pty Ltd Magnesium process
IL112385A (en) * 1994-01-21 1998-08-16 Flamemag International Gie Process for preparing magnesium hydroxide for extinguishing flames
AU695293B2 (en) * 1994-12-02 1998-08-13 Qmc (Flamemag) Pty Ltd Magnesium process
US7514489B2 (en) * 2005-11-28 2009-04-07 Martin Marietta Materials, Inc. Flame-retardant magnesium hydroxide compositions and associated methods of manufacture and use

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1348988A (en) * 1920-08-10 louis
GB403860A (en) * 1932-05-24 1934-01-04 American Zinc Lead & Smelting Improved processes for making magnesium hydroxide
US1986509A (en) * 1932-05-24 1935-01-01 American Zinc Lead & Smelting Process for making magnesium hydroxide
GB693108A (en) * 1949-10-14 1953-06-24 Wintershall Ag Process for the production of easily filterable magnesia and ammonium-magnesium-double salt
GB939467A (en) * 1960-10-12 1963-10-16 Negev Phosphates Ltd Production of magnesium hydroxide
US3508869A (en) * 1966-11-04 1970-04-28 Dow Chemical Co Novel crystalline mg(oh)2 and mgo and methods of preparation
US3711600A (en) * 1970-12-22 1973-01-16 Atomic Energy Commission Process for preparing calcined oxides
SU967954A1 (ru) * 1980-03-12 1982-10-23 Предприятие П/Я В-8046 Способ получени окиси магни

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR755409A (fr) * 1932-05-24 1933-11-24 American Zinc Perfectionnements aux procédés de fabrication d'hydrate de magésium
JPS56109820A (en) * 1980-02-06 1981-08-31 Shin Nippon Kagaku Kogyo Co Ltd Manufacture of magnesium hydroxide
JPS59210963A (ja) * 1983-05-17 1984-11-29 Mitsui Petrochem Ind Ltd ポリ―１―ブテン樹脂組成物

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1348988A (en) * 1920-08-10 louis
GB403860A (en) * 1932-05-24 1934-01-04 American Zinc Lead & Smelting Improved processes for making magnesium hydroxide
US1986509A (en) * 1932-05-24 1935-01-01 American Zinc Lead & Smelting Process for making magnesium hydroxide
GB693108A (en) * 1949-10-14 1953-06-24 Wintershall Ag Process for the production of easily filterable magnesia and ammonium-magnesium-double salt
GB939467A (en) * 1960-10-12 1963-10-16 Negev Phosphates Ltd Production of magnesium hydroxide
US3508869A (en) * 1966-11-04 1970-04-28 Dow Chemical Co Novel crystalline mg(oh)2 and mgo and methods of preparation
US3711600A (en) * 1970-12-22 1973-01-16 Atomic Energy Commission Process for preparing calcined oxides
SU967954A1 (ru) * 1980-03-12 1982-10-23 Предприятие П/Я В-8046 Способ получени окиси магни

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT392774B (de) * 1989-05-05 1991-06-10 Veitscher Magnesitwerke Ag Feinpulveriges magnesiumhydroxid und verfahren zu dessen herstellung
US5286285A (en) * 1989-05-05 1994-02-15 Veitscher Magnesitwerke-Actien-Gesellschaft Finely powdery magnesium hydroxide and a process for preparing thereof
US5143965A (en) * 1990-12-26 1992-09-01 The Dow Chemical Company Magnesium hydroxide having fine, plate-like crystalline structure and process therefor
DE4319372A1 (de) * 1993-05-26 1994-12-01 Duslo Sp Magnesiumhydroxid und Verfahren zur dessen Herstellung
US5476642A (en) * 1993-05-26 1995-12-19 Duslo, A.S. Magnesium hydroxide and process for production thereof
US6214313B1 (en) 1999-04-13 2001-04-10 Dravo Lime, Inc. High-purity magnesium hydroxide and process for its production
CN100366684C (zh) * 2002-03-11 2008-02-06 默克专利股份有限公司 底质颜料及其制备方法
EP1344800A1 (en) * 2002-03-11 2003-09-17 MERCK PATENT GmbH Body pigment and process for preparing the same
US20070152201A1 (en) * 2006-01-05 2007-07-05 Headwaters Nanokinetix, Inc. Magnesium hydroxide nanoparticles, methods of making same and compositions incorporating same
US7686986B2 (en) 2006-01-05 2010-03-30 Headwaters Technology Innovation, Llc Magnesium hydroxide nanoparticles, methods of making same and compositions incorporating same
US7771682B2 (en) 2006-01-31 2010-08-10 Council Of Scientific And Industrial Research Process for the preparation of magnesia (MgO) from crude Mg (OH)2
US20100172812A1 (en) * 2006-01-31 2010-07-08 Council Of Scientific & Industrial Research Process for the preparation of magnesia (mgo)
US20070191214A1 (en) * 2006-01-31 2007-08-16 Pushpito Kumar Ghosh Process for the preparation of magnesia (MgO) from crude Mg (OH)2
US7811535B2 (en) 2006-01-31 2010-10-12 Council Of Scientific & Industrial Research Process for the preparation of magnesia (MGO)
US20070219081A1 (en) * 2006-03-15 2007-09-20 Council Of Scientific & Industrial Research Process for the preparation of magnesia (MgO)
US10822544B2 (en) * 2013-10-29 2020-11-03 Joint Stock Company Kaustik Nanoparticles of flame retardant magnesium hydroxide and method of production the same
WO2015089685A1 (zh) * 2013-12-16 2015-06-25 刘登富 一种阻燃剂的制备方法
CN106673027A (zh) * 2016-12-30 2017-05-17 安徽壹石通材料科技股份有限公司 一种六角片状氢氧化镁阻燃剂的制备合成方法
EP4112553A1 (de) 2021-06-29 2023-01-04 Nabaltec AG Verfahren zur herstellung von magnesiumhydroxid
CN114890445A (zh) * 2022-06-08 2022-08-12 辽宁麦格尼科技有限公司 一种连续液膜合成超细氢氧化镁的方法
CN114890445B (zh) * 2022-06-08 2024-01-26 辽宁麦格尼科技有限公司 一种连续液膜合成超细氢氧化镁的方法

Also Published As

Publication number Publication date
EP0214494B1 (en) 1992-06-24
JPH0465011B2 (enrdf_load_stackoverflow) 1992-10-16
JPS62123014A (ja) 1987-06-04
DE3685782D1 (de) 1992-07-30
EP0214494A3 (en) 1989-10-11
CA1254717A (en) 1989-05-30
EP0214494A2 (en) 1987-03-18
DE3685782T2 (de) 1993-01-28

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